(A) Inhibition of RNA synthesis in CLL primary cells treated with SGI-1776. CLL primary cells (patients 3, 4, and 14) were incubated with 0.1% DMSO alone or with 0.3, 1, 3, or 10 μmol/L SGI-1776 for 24 hours. Then, 1 hour before the cells were harvested, [³H]uridine was added to the cell culture as described in “Uridine incorporation.” The results represent an average of triplicate experiments ± SEM. (B) Time-dependent reduction of MCL-1 transcript levels in CLL cells treated with SGI-1776. CLL primary cells (patients nos. 15, 16, and 17) were treated with 0.1% vehicle DMSO alone or 10 μmol/L SGI-1776 for 0, 2, 4, 8, and 24 hours, and then the RNA was isolated. MCL-1 transcript levels were measured by the use of real-time RT-PCR and normalized with 18S transcripts. Each RNA sample was assayed in triplicate, and the results are expressed as a percentage of the MCL-1 expression level in cells treated with vehicle DMSO alone. The results represent an average ± SEM of triplicate experiments. (C) Dose-dependent reduction of MCL-1 transcript levels in CLL cells treated with SGI-1776. CLL primary cells (patients nos. 2, 4, 12, and 14) were treated with 0.1% vehicle DMSO alone or with 0.3, 1, 3, or 10 μmol/L SGI-1776 for 24 hours, and transcript levels were measured in triplicate using real-time RT-PCR, and normalized with 18S transcript.